Friction shock absorber



cs. E. DATH Juy' 9, 1946.

lled Feb. '7, 1944 Patented July 9, 1946 FRICTION. SHOCK ABSOEBER George E. Dath, Chicago, Illa, assignor to H.

Miner, Inc., Chicago, Ill., a corporation of'Dela- Ware;

Application. February 7, 1944, Serial Nm .521,329l

This invention. relates to improvements in friction shock absorbers, especially adapted for use with truck' springs' of' railway cars for snubbing or dampening the action of. the springs,

One object of the invention is' to provide a friction shock absorber comprising a friction post; a pair of' rockable friction shoes having sliding engagement with the post; and spring resistance means surrounding the post' and shoes andopposing relativelengthwise movement of the same", wherein the spring resistance also presses the shoes into tight frictional contact with lthe post.

A more specific object of the invention is to provide a mechanism', as specified-in the preceding paragraph, wherein the friction shoes are provided with laterally projecting flanges forming relatively long lever arms on which the spring resistance' bears to rock the shoes toward the post. f

Other objects of the invention Will more clearly appear from the description and claims hereinafter following. f

Inthedrawing formingr a part of this specilication, Figure l is a central transverse vertical sectional View of my improved friction shock absorber. Figure 2 is a transverse horizontal sectional' view, corresponding substantially to the line 2'-2 of Figure l. Figure 3 is a top plan view of Figure l. one of the friction shoes of the device, looking from right to left in Figure l, and showing the shoe at the left hand side of said figure.

As shown in the drawing, my improved shock absorber comprises broadly a friction post A; two friction shoes' B and C; and a spring resistance D.

The friction post comprises a relatively wide, heavy platelike portion Il), which forms the post Vmember proper, having a laterally projecting,

annular flange at the lower end, which is in the form of a heavy disc, having an upwardly offset, central portion I2, which is formed with a central seat or recess |31, adapted to accommodate the usual spring centering projection of the bottom spring plate of the truck spring cluster of the railway car. The post member proper |0 upstands from the disclike portion I and is pro-- vided with substantially fiat Vfriction surfaces M-M on opposite' sides thereof, which are pref- Figure 4 is an elevational view of 7v oraims. (o1. 21671-9 il er'ably parallel to the longitudinal, central axis of F 2 sentlng downwardly facing, horizontal stop shoulders.

The two friction shoes B and C are identical in design. Referring first tothe shoe B, the same comprises1 a substantially semi-circular, flat, pl-atelike follower portion I6' and anarm |"If` depending from said follower portion. At the upper end of the arm VI, immediately below the follower portion |6 and downwardly offset therefrom, is a laterally extending', horizontally disposed, plate.- like flange I9; The flange |18 projects from the inner side of the-shoe B andr is broadly of L- shaped outline, in plan, having a right: angularly projecting, outer end portion t9v and a straight portion 20 connecting said portion t9 to the arm II. The outer edgev of the flange If8 is rounded, as indicated at 2|, said rounded edge being concentric to and in vertical alignment withY the outer edge of the platelike follower of the shoe- C. The inner edge of the straight portion 2|] of the flange I8, which edge is indicated by 22,. is substantially straight and extends radial-ly from the vertical central axis of the mechanism, at right angles to the diametrical side edge of the platelike follower I. The flange I8, in effect., forms. an offset continuation of the follower I6. and. provides a lever arm on. said follower for rocking the shoe toward the post A.

At the outer or lower end portion thereof, the arm ll df the shoe B presents a longitudinally, substantially flat, friction surface. 23, which is vertically disposed and engages the corresponding friction surface I4 of thepost A. The inner side of the arm I1 of the shoe Bis `,cut away, inwardly of the friction surface, as indicated at 24, thereby presenting'a. horizontally disposed stop shoulder 25, adapted to engage beneath the flange |5 at the corresponding side of the post A to limit longitudinal separation of' the post and shoe. The outer side of the shoe is inclined upwardly and outwardly and the surface of said outer side is transversely curved. The outer side thus presents a conical surface 26, which merges with the outer surface 2l of the upperv end portion of the shoe, which outer surface 21 is substantially cylindrical'.

Referring to the Vfriction shoe C, which as hereinbefore stated is identical with the shoe B, the platelike follower is indicated by H6, the depending arm by I I1, the flange by IIB, the right angular end and the straight portions of the flange I' I 8 by ||9 and |29, respectively, the rounded outer edge of the end ||9 by |2|, the straight inner edge of the portion IZilv by |22', the friction surface ofthe arm I by |23, the out away portion of the arm IIT by |24, the stop shoulder by |25,

3 and the outer conical surface of the shoe C by |26.

The friction shoes B and C are disposed on opposite sides of the post A with the friction surfaces 23 and |23 thereof engaging the friction surfaces |4|4 of the post, the shoe B being disposed at the left hand side and the shoe C at the right hand side of the post, as seen in Figure 1. The platelike followers IG and IIB of the shoes B and C are in abutment with each other along their diametrical inner edges, and the straight inner edges 22 and |22 of the flanges I8 and ||8 of said shoes are also in abutment with each other, the flange I8 of the shoe B being disposed at the right hand side, and the fiange ||8 of the shoe C at the left hand side of the mechanism, as

seen in Figure 1, the flange I8 of the shoe B being below the follower ||6 of the shoe C, and the flange ||8 of the shoe C being below the follower I6 of the shoe B. To accommodate the straight portions 20 and |20 of the flanges I8 and 8 of the shoes B and C and also facilitate assembling of the parts of the mechanism, the arms or plate sections |I and I|'I of the shoes are cut away, the shoe B, as indicated at 28, and the shoe C, in a similar manner.

At the center of the mechanism, the plate like followers I6 and I|6 of the two shoes B and C arev provided with an upwardly opening seat to accommodate the usual spring centering projection or boss of the upper spring plate of the truck spring cluster, the followers I6 and I'IB being recessed, as indicated at 29, to provide said seat.

The spring resistance D is in the form of a heavy coil surrounding the post and friction shoes and bears at its top and bottom ends, respectively, on the flanges or'lever arms |8| I8 of the shoes B and C and the annular flange of the platelike portion or follower I of the post A.

The spring D is preferably under initial compression and holds the shoes against the friction surfaces of the post, due tothe pressure exerted on the flanges or lever arms I 8 and I I8 thereof.

In assembling the parts of my improved friction shock absorber, the shoes B and C are first connected to each other by interengaging the platelike followers I6 and IIS thereof by sliding the same laterally toward each other along their diametrical inner edges. With the parts inverted with respect to the position shown in Figure 1, that is, with the followers of the shoes resting on a suitable support, thespring D is placed around the shoes, and the upper ends of the shoes are spread apart to admit the head of the post A therebetween. The post is then applied by inserting the same downwardly within the coil spring D and entering the same between the tilted shoes B and C. As the post A is forced downwardly, the spring-D is compressedagainst the flanges or lever arms |8-II8 of the shoes. 'I'he post is forced downwardly until the stop flanges I |5 thereof are at a level below the shoulders 25 and |25'of the shoes, and engage underneath the same, thereby bringing the parts to the assembled position, as shown in Figure 1, with the exception that the shock absorber is in inverted position with respect to Figure 1.

Although the shock absorber has been illustrated in the drawing, with the post at the lower end and the shoes at the upper end thereof, it will be evident that the same may be used as a snubber either in the position shown, or bodily inverted, with the shoes arranged at the bottom and the post at the top.

My improved shock absorber is substituted for one or more of the coil spring units of a cluster of truck springs, the same being interposed between the top and bottom spring follower plates of said cluster.

The operation of the improved shock absorber is as follows: Upon the cluster of springs of a railway car truck being compressed between the spring follower plates of the truck springs, the shoes B and C and the friction post A are moved toward each other in lengthwise direction against the resistance of the spring D. Due to the initial compression of the spring, which bears on the lever arms I8 and ||8 of the shoes, the shoes which fulcrum on the spring follower plates of the spring cluster are pressed against the post, thereby producing the desired frictional resistance. As the spring is compressed during operation of the mechanism, the pressure on the lever arms of the shoes increases, thus pressing the shoes against the friction surfaces of the post with increasing force, whereby the frictional resistance and snubbing of the shock absorber is progressively increased as compression of the mechanism progresses. The desired high frictional resistance is thus produced between the friction surfaces of the post and shoes to properly snub the action of the railway car truck springs. Compression of the `mechanism is positively limited by engagement between the lower ends of the shoes B and C and the offset I2 of the disclike plate portion lu of the post A. Upon the spring follower plates of the truck springs being moved apart, during recoil of the truck springs, the expansive action of the spring D restores all of the parts to the normal release position shown in Figure 1, separation of the post and shoes in lengthwise direction being limited by engagement of the stop flanges |5-I5 of the post with the shoulders 25 and |25 of the shoes.

As will be evident, the frictional resistance provided by the shock absorber during restoration of the parts to normal position serves to also snub the action of the truck springs in recoil.

I have herein shown and described what I now consider the preferred manner of carrying out my invention, but the same is merely illustrative and I contemplate all changes and modifications that come within the scope of the claims appended hereto.

Iclaim: v

1. In a friction shock absorbing mechanism, the combination with a friction post having longitudinally extending friction surfaces; of a pair of friction shoes embracing said post and having lengthwise sliding engagement with the friction surfaces thereof, each shoe having a follower member at the outer end thereof, said follower member being at one side of said shoe; a, laterally projecting lever arm on the other side of said shoe; and spring means surrounding said post and shoes and opposing relative lengthwise movement thereof toward each other, said spring bearing on the lever arms ofthe shoes to tilt the same against said post.

2. In a friction shock absorbing mechanism, the combination with a friction post having longitudinally extending friction surfaces on opposite sides thereof; of a pair of friction shoes embracing said post at opposite sides, said shoes having longitudinally extending friction surfaces at their inner ends on the inner sides thereof engaging the friction surfaces of the post, each shoe having a follower member at the outer end thereof; a laterally projecting lever arm on each shoe projecting from the friction surface side thereof and extending beyond the other shoe; and spring means surrounding said post and opposing relative lengthwise movement thereof toward said shoes, said spring means bearing on the lever arms of the shoes to tilt the same against the post.

3. In a friction shock absorbing mechanism, the combination with a friction post having a follower plate member at one end thereof, said post having longitudinally extending friction surfaces at opposite sidesr thereof; of apair of friction shoes embracing said post at opposite sides, said shoes having longitudinally extending friction surfaces at their inner ends on the inner sides thereof slidably engaging the friction surfaces of said post; a laterally, outwardly projecting fc-llower flange on each shoe; a laterally extending lever arm on each shoe projecting from the friction surface side thereof, said arm being inwardy offset with respect to said follower flange; and a coil spring surrounding said shoes and post and bearing at opposite ends on the follower plate member of the post and the lever arms of the shoes.

4. In a friction shock absorbing mechanism, the combination with a vertically disposed friction post having a, horizontally disposed follower plate member at one end thereof; of a pair of friction shoes embracing said post at opposite sides in lengthwise sliding engagement therewith, said shoes having friction surfaces on the rinner sides thereof engaging said post; a horizontally disposed, laterally outwardly projecting follower flange at the outer end of each shoe; a horizontally disposed lever arm on each shoe extending from the friction surface side thereof, said lever arm being offset inwardly with respect to the flange of the shoe; and spring means opn posing relative lengthwise movement of said post and shoes toward each other, said spring bearing at opposite ends on the follower plate member of the post and the lever arms of the shoes.

5. In a friction shock absorbing mechanism, the combination with a vertically disposed friction post having longitudinally extending friction surfaces; of a pair of friction shoes embracing said post and having lengthwise sliding the combination with a vertically disposed friction post having longitudinally extending friction surfaces on opposite sides thereof; of a pair of vertically disposed friction shoes embracing said post at opposite sides, said shoes having longitudinally extending friction surfaces at their inner ends on the inner sides thereof engaging the friction surfaces of the post, said shoes having at transverse outer ends; a horizontally, laterally projecting lever arm on` each shoe projecting from the friction surface side thereof and extending beyond the. other shoe;

and spring means surrounding said post and opposing lengthwise movement of said post toward the shoes, said spring means bearing on the lever arms of the shoes to tilt the same against the post.

7. In a friction shock absorbing mechanism, the combination with a friction post having a circular, disclike follower plate member at one end thereof, said post having longitudinally extending friction surfaces at opposite sides thereof; lof a pair of friction shoes embracing said post at opposite sides, said shoes having longitudinally extending friction surfaces at their inner ends on the inner sides thereof slidably engaging thefriction surfaces'of said post; a

laterally, outwardly projecting, semi-circular follower plate on each shoe, at the outer end thereof, the follower plates of said shoes being in abutment on their diametrical inner edges; a laterally extending lever arm on each shoe projecting from the friction surface side thereof,

, said arm being inwardly offset with respect to 

